Conventional exercises for the stomach muscles include sit-ups and leg lifts. Multiple repetitions and the recommended performance of sit ups in association with a partner make these exercises unacceptable to many persons.
Appliances used for exercises of this sort include spring devices, rope and pulley systems and rubber tubing. These are all based on the leg raise and sit-up exercises and suffer from many of the same disadvantages. In addition, the exercises carried out with these devices are not specifically intended to exercise the stomach muscles. Sometimes only the the upper stomach muscles are developed. This has a negative effect in that it produces a rounded upper stomach.
Weight training can show the most rapid and thorough results, but to exercise the stomach specifically, several different exercises are required, with as much time and risk as some of the non-weight methods.